In particle beam therapy, a patient's lesion tissue (cancer) is irradiated with a particle beam such as carbon ions, and this particle beam therapy technique attracts attention.
In the particle beam treatment technique, it is possible to kill only the lesion tissue with pinpoint accuracy without damaging normal tissues. Thus, the particle beam treatment technique is less burdensome on patients than surgery, medication therapy or the like, and it can be expected to accelerate social reintegration after treatment.
In the early irradiation treatment apparatus, the irradiation portion of a particle beam was fixed, and the fixation method, in which irradiation was possible only from one direction with respect to a target, was mainstream.
In recent years, for the purpose of providing a more effective treatment, a rotation method has been spotlighted. In the rotation method, the irradiation portion of a particle beam is rotated so as to give an optimum dose value and optimum dose distribution to the lesion tissue depending on the shape of the lesion tissue and the body depth.